Environmental Radioactivity In The Plitvice Lakes National Park 1: Soil, Lake Water, And River Water

We report on a part of a study of the environmental radioactivity in the Plitvice Lakes National Park that was carried out during 2011 and 2012. This part was focused on measuring the activity concentrations of important naturally occurring (40K, 7Be, 238U, 235U, 232Th, 226Ra, 210Pb) and fission produced (90Sr, 134Cs, 137Cs) radionuclides in collected samples of soil, lake water, and river water, and also on determining the ambient dose equivalent rate H*(10)/t. Activity concentrations were determined by means of a high-resolution gamma ray spectrometry, except in the case of 90Sr for which radiochemical separation and beta counting were used. The measured values of activity concentration were similar to those in other parts of continental Croatia. H*(10)/t was determined using continuously operating ALARA electronic dosimeters, and its value between April 2011 and October 2012 amounted to 77 ± 7 nSv/h. The only unusual feature we observed were large fluctuations of H*(10)/t in April 2011, which most likely occurred due to the Fukushima accident but did not last long.(author).